Angiography (or arteriography) imaging is used to monitor and characterize cardiac tissue and functions, including morphology, blood flow, anatomy and arterial luminal size by displaying static and dynamic image silhouettes. This provides the ability to assess cardiac and coronary arterial function and to visualize a heart system (Ventricle, Atrium, Vessel), which facilitates diagnosis and determination of cardiac disease. It is desirable to minimize radiation dose used in medical imaging. Known X-ray imaging and fluoroscopic imaging typically capture images randomly or based on time and may lead to unnecessary X-ray exposure. It is known for a fluoroscopic imaging system to employ ECG or respiration signals for triggering X-ray exposure and image scanning and acquisition to avoid patient movement and unwanted electrical noise. However known image scanning and acquisition systems usually employ uniformly timed image acquisition and may fail to capture anatomical features during an ECG Q wave or S wave, for example, since the image scanning is triggered in response to an R wave.
Known image systems, such as X-ray systems, usually employ a collimator (typically a rectangle or square X-ray attenuation device) to limit X-ray beam exposure and radiation dose. However, especially in heart monitoring cases, an anatomical region of interest (ROI) area is usually not a rectangle or square which results in unnecessary radiation exposure to an area outside the ROI. Known imaging systems usually employ a fixed image scanning rate in continuous image acquisition. Known imaging systems may apply a fixed pixel resolution and radiation exposure (time interval length and intensity) in continuous image acquisition and use uniform intensity X-ray beam radiation over an entire image. A system according to invention principles addresses these deficiencies and related problems.